Various types of microprocessor-based electronic control systems for governing the speed of an engine are well known in the art. These control systems typically calculate a speed error signal based on the difference between the desired speed of the crankshaft of an engine and the actual speed of the engine crankshaft. The speed error signal is input to a controller that converts the speed error signal to a command signal. The command signal is input to an actuating device to change the engine's operating state so that the actual speed of the engine approaches the desired speed of the engine. An example of a command signal is commanded fuel valve position that is used to control the amount of fuel injected per cycle in a diesel engine. A change in the fuel delivered to the engine will cause the speed of the engine's crankshaft to accelerate or decelerate, thereby causing a change in engine speed. The magnitude and rate of change of engine crankshaft speed is a function of the engine's dynamics including the engine's inertia, the inertia of the load, and the load on the engine. The controllers have one or more gain factors associated with them to convert the engine speed error signal to the desired command signal and to achieve the desired response characteristics. In the prior art, the gain factors are selected for each system using control system analysis techniques and/or simulation models. The value selected for a gain factor may be a constant or a function of one or more variables.
Another type of speed governing system is a cruise control system that is used to control the speed of a mobile machine that is powered by an engine. A sensor provides a signal indicative of the traveling speed of the machine, such as an automobile. A desired traveling speed is set by an operator. A machine speed error signal based on the difference between the desired traveling speed and the sensed traveling speed is converted to a desired engine speed signal. This signal is input to the engine speed control system to change the speed of the engine, thereby indirectly changing the speed of the mobile machine. A gain factor that is a constant or a function of one or more variables is used to convert the machine speed error to a commanded engine speed. The gain factor is selected to achieve the desired dynamic response for the engine/machine combination.
As electronic control systems become more widely used across engines and other propulsion systems, it is desired to have an electronic control system that is independent of a particular system's dynamics. The control system would then be usable with a variety of propulsion system platforms without having to determine gain factors for a given engine or engine/machine combination. It is also desired to use such a control system to control the speed of the engine as well as the speed of vehicles and machinery that are powered by the engine.